Flow path member

Abstract

This flow path member is provided with a substrate, a flow path, and a conductive layer. The substrate is made of a ceramic. The flow path is located inside the substrate, and the substrate constitutes an inner wall surface. The conductive layer is located on the inner wall surface of the flow path. At least a part of the inner wall surface includes a first region having a surface roughness Ra of ３μｍ or greater.

Description

Flow path member

[0001] This disclosure relates to a flow path member.

[0002] Conventionally, a flow path member in which the periphery of an internal flow path is coated with a conductive layer is known (see Patent Document 1). Also known is a flow path member that releases static electricity generated by friction between a fluid and a flow path to the outside through a low-resistance layer (see Patent Document 2).

[0003] Japanese Unexamined Patent Application Publication No. 2022-011991, Japanese Unexamined Patent Application Publication No. 2016-207931

[0004] The flow path member of the present disclosure includes a substrate, a flow path, and a conductive layer. The substrate is made of ceramics. The flow path is located inside the substrate, and the substrate constitutes an inner wall surface. The conductive layer is located on the inner wall surface of the flow path. At least a part of the inner wall surface has a first region where the surface roughness Ra is 3 μm or more.

[0005] FIG. 1 is a perspective view showing an example of a flow path member according to an embodiment. FIG. 2 is a cross-sectional view taken along line II-II shown in FIG. 1. FIG. 3 is a cross-sectional view taken along line III-III shown in FIG. 2. FIG. 4 is a cross-sectional view showing an example of a flow path member according to an embodiment. FIG. 5 is a cross-sectional view taken along line V-V shown in FIG. 4. FIG. 6 is a cross-sectional view showing an example of a flow path member according to an embodiment. FIG. 7 is a cross-sectional view taken along line VII-VII shown in FIG. 6. FIG. 8 is a cross-sectional view showing an example of a modified example of the flow path member according to an embodiment. FIG. 9 is a cross-sectional view showing an example of a modified example of the flow path member according to an embodiment. FIG. 10 is a cross-sectional view showing an example of a modified example of the flow path member according to an embodiment. FIG. 11 is a cross-sectional view showing an example of a modified example of the flow path member according to an embodiment. FIG. 12 is a cross-sectional view taken along line XII-XII shown in FIG. 3. FIG. 13 is a diagram showing an example of a cooling device using an insulating cooling medium.

[0006] Hereinafter, a mode for implementing the flow path member according to the present disclosure (hereinafter referred to as "embodiment") will be described in detail with reference to the drawings. Note that the present disclosure is not limited by this embodiment. Also, the respective embodiments can be appropriately combined within a range that does not conflict with the processing content. In addition, in the following embodiments, the same parts are denoted by the same reference numerals, and redundant explanations are omitted.

[0007] Furthermore, in the drawings referenced below, for the sake of clarity, mutually orthogonal X-axis, Y-axis, and Z-axis directions are sometimes defined, and a Cartesian coordinate system is shown in which the Z-axis direction is the thickness direction of the flow channel member.

[0008] In the conventional technology described above, there was room for improvement in terms of increasing the adhesion strength between the substrate and the conductive layer.

[0009] This disclosure provides a technology that can increase the adhesion strength between a substrate and a conductive layer.

[0010] <Embodiment> First, the configuration of the flow channel member according to the embodiment will be described with reference to Figures 1 to 7 and Figure 13. Figure 1 is a perspective view showing an example of the flow channel member 1 according to the embodiment. Figure 2 is a cross-sectional view taken along line II-II in Figure 1. Figure 3 is a cross-sectional view taken along line III-III in Figure 2. Figure 4 is a cross-sectional view showing an example of the flow channel member 1 according to the embodiment. Figure 5 is a cross-sectional view taken along line V-V in Figure 4. Figure 6 is a cross-sectional view showing an example of the flow channel member 1 according to the embodiment. Figure 7 is a cross-sectional view taken along line VII-VII in Figure 6. Figure 13 is a diagram showing an example of a cooling device 2 using an insulating cooling medium 5.

[0011] As shown in Figures 1 to 3, the flow channel member 1 comprises a base body 10, a flow channel 20, and a conductive layer 30.

[0012] The substrate 10 is made of ceramics. For example, alumina, yttria, zirconia, cordierite, aluminum nitride, and silicon nitride can be used as ceramics. The substrate 10 may have a contact surface 11 that comes into contact with the object to be processed. The contact surface 11 may be, for example, a flat surface. The object to be processed may be, for example, a semiconductor wafer. In this case, the contact surface 11 may be, for example, circular in shape in plan view. Furthermore, contact with the object to be processed may be indirect contact via liquid, gas, or solid, in addition to direct contact.

[0013] The substrate 10 may have functional electrodes. The substrate 10 may also have vias and lead wires connected to the functional electrodes. Examples of functional electrodes include electrodes for electrostatic adsorption, resistance heating elements, high-frequency electrodes, and resistance thermometers such as RTDs. Examples of materials for the functional electrodes include platinum, tungsten, and molybdenum. The substrate 10 may also have a flow path other than the flow path 20. For example, other flow paths may include gas outlets for shower materials and gas holes for wafer cooling (He).

[0014] The flow path 20 is located inside the substrate 10. The flow path 20 may be a flow path for circulating a medium for cooling the electronic component to be processed. The medium may be, for example, an insulating fluid. The insulating fluid may be, for example, a fluorine-based liquid. The flow path 20 may be a meandering flow path in which the medium flows in a meandering manner. Although not shown in the figures, the flow path member 1 is provided with a supply port and an outlet that connect the flow path 20 to the outside. The supply port and outlet may be located at both ends of the flow path 20 in the flow direction, respectively.

[0015] As shown in Figure 2, the flow path 20 may have an upper and lower surface and both sides when viewed from the flow direction of the medium flowing through the flow path 20. The flow path 20 may be rectangular when viewed from the flow direction of the medium flowing through the flow path 20. The inner wall surface of the flow path 20 may have a first surface 21 which is either the upper or lower surface and a second surface 22 which is the other of the upper and lower surfaces, and a third surface 23 which is either one of the two sides connecting the first surface 21 and the second surface 22 and a fourth surface 24 which is the other of the two sides. The first surface 21 may be located on the side of the contact surface 11. The second surface 22 may be located on the opposite side of the contact surface 11. The third surface 23 and the fourth surface 24 may be located in the center of the thickness direction of the base body 10 and extend perpendicularly to the first surface 21 and the second surface 22. In this embodiment, the flow direction of the medium is the direction of the flow path 20 which meanders in the X-axis direction or the Y-axis direction.

[0016] The conductive layer 30 is located on the inner wall surface of the flow channel 20. The conductive layer 30 may completely cover the inner wall surface of the flow channel 20. The conductive layer 30 may have conductivity sufficient to discharge static electricity generated by friction between the insulating fluid and the conductive layer 30. The conductive layer 30 configured in this way can prevent the flow channel member 1 from becoming charged.

[0017] The inner wall surface has a first region A in at least a portion thereof, in which the surface roughness Ra is 3 μm or more. The first region A may be located in a part of the inner wall surface or may be located on the entire inner wall surface. For example, it is desirable that the area of ​​the first region A is 30% or more of the total surface area of ​​the inner wall surface of the flow channel 20. The surface roughness Ra in the first region A may be 3 to 7 μm.

[0018] The surface roughness Ra of the inner wall surface may be measured, for example, before forming the conductive layer 30 on the inner wall surface during manufacturing. Alternatively, the surface roughness Ra of the inner wall surface may be measured after removing the conductive layer 30 located on the inner wall surface using a sulfuric acid solution or a nitric acid solution. In this case, the concentration of the solution, the processing time, and the processing temperature should be adjusted so as not to roughen the surface. The surface roughness Ra may conform to JIS B 0601:1994 and JIS B 0031:1994. The measurement equipment may be, for example, a contact-type surface roughness meter (SURFCOM TOUCH 550 manufactured by ACCRETECH). The measurement conditions for one area may be a measurement length of 4,000 mm, a measurement speed of 0,300 mm / s, and a cutoff wavelength of 0.8 mm.

[0019] Areas other than the first area A on the inner wall surface may have different surface roughness Ra than the first area A. The surface roughness Ra of the areas different from the first area A may be 0.1 to less than 3 μm.

[0020] The conductive layer 30 may have areas of normal thickness and areas that are thicker than normal thickness. The normal thickness of the conductive layer 30 may be 0.1 to 10 μm when the cross-section of the conductive layer 30 is observed by SEM. The conductive layer 30 may be a metal conductor mainly composed of nickel, platinum, or gold. In this disclosure, the main component is, for example, a material that accounts for 50% or more by mass of the material.

[0021] According to the flow channel member 1 of this embodiment, the surface area of ​​the base body 10 is increased because the first region A is located on at least a part of the inner wall surface. Therefore, the adhesion strength between the base body 10 and the conductive layer 30 can be increased by the anchoring effect. And by increasing the adhesion strength between the base body 10 and the conductive layer 30, the reliability of the conductive layer 30 can be increased.

[0022] Furthermore, the presence of this first region A increases the contact area between the substrate 10 and the conductive layer 30, thereby improving the heat exchange efficiency between the substrate 10 and the conductive layer 30.

[0023] The flow channel member 1 may have the first region A located on the third surface 23 and the fourth surface 24. The flow channel member 1 may have the first region A located on part of the third surface 23 and the fourth surface 24, or it may have the first region A located on all of the third surface 23 and the fourth surface 24. The average value Ra1 of the surface roughness Ra on the first surface 21 and the average value Ra2 of the surface roughness Ra on the second surface 22 may be smaller than the average value Ra3 of the surface roughness Ra on the third surface 23 and the average value Ra4 of the surface roughness Ra on the fourth surface 24. For example, the first surface 21 and the second surface 22 may have regions with surface roughness Ra different from that of the first region A. The average value of the surface roughness Ra on each of these surfaces may be the average of n=5 measured values ​​on each surface. The measurement position may be, for example, by dividing the flow channel from the inlet to the outlet into six equal parts from the first region to the sixth region, and measuring at each boundary.

[0024] According to the flow channel member 1 of this embodiment, the surface area of ​​the substrate 10 on the third surface 23 and the fourth surface 24 is increased, which increases the adhesion strength of the conductive layer 30 on surfaces where the flowing medium changes direction or collides. Therefore, the conductive layer 30 is less likely to peel off on surfaces where the flowing medium changes direction or collides. In addition, since the average surface roughness Ra1 on the first surface 21 and the average surface roughness Ra2 on the second surface 22 are smaller than the average surface roughness Ra3 on the third surface 23 and the average surface roughness Ra4 on the fourth surface 24, the first surface 21 and the second surface 22 are less likely to obstruct the flow of the medium, thus reducing the decrease in cooling rate.

[0025] As shown in Figures 4 and 5, the first region A may be located on the first surface 21 and the second surface 22 of the flow channel member 1. The first region A may be located on all of the first surface 21 and the second surface 22 of the flow channel member 1, or on parts of the first surface 21 and the second surface 22. The average surface roughness Ra3 on the third surface 23 and the average surface roughness Ra4 on the fourth surface 24 may be smaller than the average surface roughness Ra1 on the first surface 21 and the average surface roughness Ra2 on the second surface 22. For example, regions with a different surface roughness Ra than the first region A may be located on the third surface 23 and the fourth surface 24.

[0026] According to the embodiment of the flow channel member 1, the surface area of ​​the substrate 10 on the first surface 21 and the second surface 22 is increased, so the heat exchange efficiency can be increased in the thickness direction of the substrate 10. In addition, since the average surface roughness Ra3 on the third surface 23 and the average surface roughness Ra4 on the fourth surface 24 are smaller than the average surface roughness Ra1 on the first surface 21 and the average surface roughness Ra2 on the second surface 22, the third surface 23 and the fourth surface 24 are less likely to obstruct the flow of the medium, so the decrease in cooling rate can be reduced.

[0027] Furthermore, at least a portion of the surface of the conductive layer 30 may have a region with a surface roughness Ra of less than 3 μm. The conductive layer 30 may have a region with a surface roughness Ra of less than 3 μm on a portion of its surface, or the entire surface of the conductive layer 30 may have a region with a surface roughness Ra of less than 3 μm.

[0028] According to the flow channel member 1 of this embodiment, at least a portion of the surface of the conductive layer 30 has a region with a surface roughness Ra of less than 3 μm, so that the flow of the medium by the conductive layer 30 is not easily obstructed. Therefore, the flow channel member 1 can facilitate the smooth flow of the medium.

[0029] As shown in Figure 6, the flow channel 20 and the conductive layer 30 may have corners C1 when viewed from the direction of flow of the medium flowing through the flow channel 20. The corners C1 of the conductive layer 30 may be curved in an arc shape when viewed from the direction of flow. For example, the flow channel 20 and the conductive layer 30 may have four corners C1.

[0030] Furthermore, the shape of the channel 20 as viewed from the direction of flow of the medium flowing through it is not particularly limited. Therefore, the channel 20 and the conductive layer 30 are not limited to the example in Figure 6, and may have, for example, three corners C1 or five or more corners C1. Also, the corners C1 of the conductive layer 30 may all be curved in an arc shape as viewed from the direction of flow, or some of the corners C1 may be curved in an arc as viewed from the direction of flow.

[0031] According to the flow channel member 1 of this embodiment, the corners C1 of the conductive layer 30, as viewed from the flow direction, have a rounded shape, and the medium flows inside the conductive layer 30 having the corners C1. Therefore, the flow of the medium becomes smoother.

[0032] As shown in Figure 7, the channel 20 and the conductive layer 30 have corners C2 located at points P where the flow direction of the medium flowing through the channel 20 changes. When viewed from a direction perpendicular to the contact surface 11, the corners C2 of the conductive layer 30 are curved in an arc shape. For example, at point P where the flow direction of the medium changes from the X-axis direction to the Y-axis direction, or from the Y-axis direction to the X-axis direction, two corners C2 are located in the channel 20 and the conductive layer 30, respectively.

[0033] Furthermore, the shape of the flow channel 20 as viewed from a direction perpendicular to the contact surface 11 is not particularly limited. Therefore, the flow channel 20 and the conductive layer 30 have corners C2 according to the shape of the flow channel 20 as viewed from a direction perpendicular to the contact surface 11, not limited to the example in Figure 7. Also, the corners C2 of the conductive layer 30 may be curved in an arc shape at all corners C2 at locations P where the flow direction of the medium flowing through the flow channel 20 changes, or some corners C2 at locations P where the flow direction of the medium flowing through the flow channel 20 changes may be curved in an arc.

[0034] According to the flow channel member 1 of this embodiment, the corners C2 of the conductive layer 30, when viewed from a direction perpendicular to the contact surface 11, have a rounded shape, and the medium flows along the shape of the conductive layer 30 having these corners C2. Therefore, the flow of the medium becomes smoother.

[0035] As described above, the flow channel member 1 can be used as a heat absorption member for the object to be processed, but as shown in Figure 13, it can also be used as a heat dissipation member that releases heat from an insulating fluid that has heated up by cooling a high-temperature object. For example, when the flow channel member 1 is used as a heat dissipation member for electronic components 4 such as semiconductor devices and sensors located in an electronic device 3 such as a data center, server, or base station, the flow channel member 1 and the electronic components 4, which are the object to be processed, may be located far apart. The flow channel member 1 may be connected to the electronic device 3 via a pipe 6, and for example, an insulating cooling medium 5 may be circulated between the flow channel member 1 and the electronic device 3 through the pipe 6 by a pump (not shown). A metal heat receiving member 7 may be located in the flow channel member 1. The heat receiving member 7 may be connected to a heat dissipation device 9 such as a fan via a pipe 8, and heat may be dissipated from the heat dissipation device 9 to the atmosphere.

[0036] <Modified Examples> Next, modified examples of the flow channel member 1 according to the embodiment will be described with reference to Figures 8 to 11. Figures 8 to 11 are cross-sectional views showing an example of a modified example of the flow channel member 1 according to the embodiment. In the following, the first region A is not shown.

[0037] As shown in Figure 8, the flow path 20 may have corners C3 when viewed from the direction of flow of the medium flowing through the flow path 20. At least one corner C3 may be curved in an arc shape when viewed from the direction of flow of the medium.

[0038] According to the flow channel member 1 of this embodiment, the corner C3 of the flow channel 20, as viewed from the direction of the flow of the medium, has a rounded shape, and the medium flows inside the conductive layer 30 which curves along the corner C3. Therefore, the flow of the medium becomes smoother.

[0039] Specifically, the flow path 20 may have four corners C3 when viewed from the flow direction. Two corners C3 may be located on the first surface 21 side and two on the second surface 22 side. The two corners C3 located on the second surface 22 side may be curved in an arc shape. The conductive layer 30 may be curved in an arc shape along the two corners C3 located on the second surface 22 side.

[0040] According to the flow path member 1 according to the embodiment, the corner C3 located on the second surface 22 side has a rounded shape, and the medium flows inside the conductive layer 30 that curves along the corner C3. Therefore, the flow of the medium on the second surface 22 side becomes smoother.

[0041] As shown in FIG. 9, the flow path 20 may be rectangular having four corners C3 when viewed from the flow direction. All of the four corners C3 may be curved in an arc shape. The conductive layer 30 may be curved in an arc shape along the four corners C3.

[0042] According to the flow path member 1 according to the embodiment, the corners C3 on the first surface 21 side and the second surface 22 side have a rounded shape, and the medium flows inside the conductive layer 30 that curves along the corner C3. Therefore, the flow of the medium on the first surface 21 side and the second surface 22 side becomes smoother.

[0043] As shown in FIG. 10, the flow path 20 may have a step portion 27 when viewed from the flow direction of the medium flowing through the flow path 20.

[0044] According to the flow path member 1 according to the embodiment, the surface area of the base body 10 increases. Therefore, the heat exchange efficiency between the base body 10 and the conductive layer 30 can be enhanced.

[0045] Specifically, the flow path 20 may each have a step portion 27 connecting the inner wall surface on the first surface 21 side and the inner wall surface on the second surface 22 side on one side and the other side in the direction parallel to the first surface 21. One step portion 27 may connect the inner wall surface 25a on the first surface 21 side and the inner wall surface 26a on the second surface 22 side of the flow path 20. The other step portion 27 may connect the inner wall surface 25b on the first surface 21 side and the inner wall surface 26b on the second surface 22 side of the flow path 20. The two step portions 27 may each have a step where the width W of the flow path 20 in the direction parallel to the first surface 21 increases from the second surface 22 side toward the first surface 21 side. The step may be such that the inner wall surface of the flow path 20 is refracted at a right angle.

[0046] The corner portions C3 may be respectively positioned on the first surface 21 side of the step portion 27. Further, the corner portions C3 may be respectively positioned on the second surface 22 side of the step portion 27. By having the step portion 27, the flow path 20 may have a shape in which the first surface 21 side expands in a direction parallel to the first surface 21 more than the second surface 22 side. Although all four corner portions C3 are curved in an arc shape when viewed from the flow direction, they are not particularly limited and may be bent at a right angle.

[0047] Alternatively, as shown in FIG. 11, one of the step portions 27 may have a step such that the width W of the flow path 20 in the direction parallel to the first surface 21 increases from the second surface 22 side toward the first surface 21 side. The other step portion 27 may have a step such that the width W of the flow path 20 in the direction parallel to the first surface 21 decreases from the second surface 22 side toward the first surface 21 side. The step may be such that the inner wall surface of the flow path 20 is bent at a right angle.

[0048] The corner portions C3 may be respectively positioned on the first surface 21 side of the step portion 27. Further, the corner portions C3 may be respectively positioned on the second surface 22 side of the step portion 27. By having the step portion 27, the flow path 20 may have a shape in which the first surface 21 side and the second surface 22 side are displaced in a direction parallel to the first surface 21. Although all four corner portions C3 are curved in an arc shape when viewed from the flow direction, they are not particularly limited and may be bent at a right angle.

[0049] According to the flow path member 1 according to the embodiment, the surface area of the base body 10 in the step portion 27 is increased. Therefore, the heat exchange efficiency between the base body 10 and the conductive layer 30 in the step portion 27 can be enhanced.

[0050] <Usage Example> Next, a specific usage example of the flow path member 1 of the present disclosure will be described.

[0051] Examples of applications for the flow channel member 1 include heat exchangers using insulating cooling refrigerants for semiconductor manufacturing equipment and semiconductor inspection equipment. Examples of applications for heat exchangers include electrostatic chucks, heaters, shower plates, and dielectric windows (top plates, lids). Another example of applications for the flow channel member 1 is, as shown in Figure 13, a component for immersion cooling devices for semiconductor devices, electronic devices, etc., that use an insulating cooling medium 5. Yet another example of applications for the flow channel member 1 is a component for a refrigeration circuit or a freezing circuit in air conditioning equipment that uses an insulating cooling refrigerant.

[0052] <Manufacturing Method> Next, a method for manufacturing the flow channel member 1 of this disclosure will be described with reference to Figure 12. Figure 12 is a cross-sectional view taken along the line XII-XII shown in Figure 3.

[0053] As a method for manufacturing the flow channel member 1, one method is to form the flow channel 20 by a lamination method including tape punching, laser, or cutting, and then perform firing. As a method for forming the conductive layer 30, one method is to use electroless plating. As a method for adjusting the surface roughness Ra, one method is to adjust the processing conditions such as laser or cutting during flow channel formation. As a method for adjusting the thickness of the conductive layer 30, one method is to adjust conditions such as the electroless plating time and the rate at which the plating solution is flowed.

[0054] Finally, the formation of the conductive layer 30 will be described. As shown in Figure 12, the through hole 40 may be located from the flow path 20 toward the surface 12 opposite to the contact surface 11. The inner wall surface of the through hole 40 may be covered with the conductive layer 30. This allows the conductive layer 30 to function as a ground and, by connecting to an external conductor (not shown) that dissipates static electricity, prevents static electricity from building up due to friction between the conductive layer 30 and the medium. The through hole 40 may also be a supply port or outlet for the medium.

[0055] Although the present disclosure has been described in detail above, this disclosure is not limited to the embodiments described above, and various modifications and improvements are possible without departing from the gist of this disclosure.

[0056] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. Indeed, the embodiments described above can be embodied in a variety of forms. Furthermore, the embodiments described above may be omitted, replaced, or modified in various ways without departing from the scope and spirit of the appended claims.

[0057] Furthermore, this technology can also take the following configurations. <Note> (1) A flow channel member comprising: a substrate made of ceramics; a flow channel located inside the substrate and the substrate constituting an inner wall surface; and a conductive layer located on the inner wall surface, wherein at least a part of the inner wall surface has a first region having a surface roughness Ra of 3 μm or more. (2) The flow channel has upper and lower surfaces and both sides when viewed from the flow direction of the medium flowing through the flow channel, the inner wall surface has a first surface which is either one of the upper and lower surfaces and a second surface which is the other of the upper and lower surfaces, a third surface which is either one of the two sides connecting the first surface and the second surface and a fourth surface which is the other of the two sides, the average value Ra1 of the surface roughness Ra on the first surface and the average value Ra2 of the surface roughness Ra on the second surface are smaller than the average value Ra3 of the surface roughness Ra on the third surface and the average value Ra4 of the surface roughness Ra on the fourth surface, the flow channel member according to (1). (3) The flow channel member according to (1), wherein the flow channel has an upper and lower surface and both sides when viewed from the direction of flow of the medium flowing through the flow channel, the inner wall surface has a first surface which is one of the upper and lower surfaces and a second surface which is the other of the upper and lower surfaces, a third surface which is one of the two sides connecting the first and second surfaces and a fourth surface which is the other of the two sides, and the average value Ra3 of the surface roughness Ra on the third surface and the average value Ra4 of the surface roughness Ra on the fourth surface are smaller than the average value Ra1 of the surface roughness Ra on the first surface and the average value Ra2 of the surface roughness Ra on the second surface. (4) The flow channel member according to any one of (1) to (3), wherein at least a portion of the surface of the conductive layer has a region where the surface roughness Ra is less than 3 μm. (5) The flow channel member according to any one of (1) to (4), wherein the flow channel has a stepped portion when viewed from the direction of flow of the medium flowing through the flow channel.(6) The flow path member according to (5), wherein the flow path has upper and lower surfaces when viewed from the direction of flow of the medium flowing through the flow path, the inner wall surface has a first surface which is one of the upper and lower surfaces and a second surface which is the other of the upper and lower surfaces, the stepped portion is located on one side and the other side of the inner wall surface in a direction parallel to the first surface, connecting the inner wall surface on the first surface side and the inner wall surface on the second surface side, and each step has such that the width of the flow path in the direction parallel to the first surface increases from the second surface side to the first surface side. (7) The flow path member according to (5), wherein the flow path has upper and lower surfaces when viewed from the direction of flow of the medium flowing through the flow path, the inner wall surface has a first surface which is one of the upper and lower surfaces and a second surface which is the other of the upper and lower surfaces, the stepped portion is located on one side and the other side of the inner wall surface in a direction parallel to the first surface, and connects the inner wall surface on the first surface side and the inner wall surface on the second surface side, one of the stepped portion has a step in which the width of the flow path in a direction parallel to the first surface increases from the second surface side to the first surface side, and the other stepped portion has a step in which the width of the flow path in a direction parallel to the first surface decreases from the second surface side to the first surface side.

[0058] 1 Channel member 10 Base 11 Contact surface 20 Channel 21 Top surface, first surface 22 Bottom surface, second surface 23 Side surface, third surface 24 Side surface, fourth surface 25a Inner wall surface 25b Inner wall surface 26a Inner wall surface 26b Inner wall surface 27 Step part 30 Conductive layer A First region C1 Corner C2 Corner C3 Corner P Location

Claims

1. A flow channel member comprising: a substrate made of ceramics; a flow channel located inside the substrate and where the substrate constitutes an inner wall surface; and a conductive layer located on the inner wall surface, wherein at least a portion of the inner wall surface has a first region having a surface roughness Ra of 3 μm or more.

2. The flow path has an upper and lower surface and both sides when viewed from the direction of flow of the medium flowing through the flow path, the inner wall surface has a first surface which is one of the upper and lower surfaces and a second surface which is the other of the upper and lower surfaces, a third surface which is one of the two sides connecting the first surface and the second surface and a fourth surface which is the other of the two sides, the average value Ra1 of the surface roughness Ra on the first surface and the average value Ra2 of the surface roughness Ra on the second surface are smaller than the average value Ra3 of the surface roughness Ra on the third surface and the average value Ra4 of the surface roughness Ra on the fourth surface, the flow path member according to claim 1.

3. The flow path has an upper and lower surface and both sides when viewed from the direction of flow of the medium flowing through the flow path, the inner wall surface has a first surface which is one of the upper and lower surfaces and a second surface which is the other of the upper and lower surfaces, a third surface which is one of the two sides connecting the first and second surfaces and a fourth surface which is the other of the two sides, the average value Ra3 of the surface roughness Ra on the third surface and the average value Ra4 of the surface roughness Ra on the fourth surface are smaller than the average value Ra1 of the surface roughness Ra on the first surface and the average value Ra2 of the surface roughness Ra on the second surface, the flow path member according to claim 1.

4. The flow channel member according to any one of claims 1 to 3, wherein at least a portion of the surface of the conductive layer has a region with a surface roughness Ra of less than 3 μm.

5. The flow channel member according to any one of claims 1 to 4, wherein the flow channel has a stepped portion when viewed from the direction of flow of the medium flowing through the flow channel.

6. The flow path member according to claim 5, wherein the flow path has upper and lower surfaces when viewed from the direction of flow of the medium flowing through the flow path, the inner wall surface has a first surface which is one of the upper and lower surfaces and a second surface which is the other of the upper and lower surfaces, the stepped portion is located on one side and the other side of the inner wall surface in a direction parallel to the first surface, connecting the inner wall surface on the first surface side and the inner wall surface on the second surface side, and each step has such that the width of the flow path in the direction parallel to the first surface increases from the second surface side to the first surface side.

7. The flow path member according to claim 5, wherein the flow path has upper and lower surfaces when viewed from the direction of flow of the medium flowing through the flow path, the inner wall surface has a first surface which is one of the upper and lower surfaces and a second surface which is the other of the upper and lower surfaces, the stepped portions are located on one side and the other side of the inner wall surface in a direction parallel to the first surface, and connect the inner wall surface on the first surface side and the inner wall surface on the second surface side, one of the stepped portions has a step in which the width of the flow path in a direction parallel to the first surface increases from the second surface side to the first surface side, and the other stepped portion has a step in which the width of the flow path in a direction parallel to the first surface decreases from the second surface side to the first surface side.

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